There are stark differences in the observed concentrations when compared with that of urban areas.
Well yes, I read enough of the article to understand this is what they meant but also that there was large unexplained variations (noise) so I just gave up. I don’t have the resources, knowledge and the time to conduct a good, complete analysis.
Why shill for oil at the expense of your own health?
Now this is a multi-billion dollar question and before they shut down the tar sands, many more studies will be made. So, it’s not for me to decide and we will have the opportunity to see more in this battle.